In co-pending co-owned patent 4,378,018, there is disclosed a male urinary drainage device composed of a thin resilient external catheter and an underlying adhesive sealant pad for holding the catheter in place and for producing an effective seal to prevent urine backup and leakage. The pad is formed of compressible, deformable, water-resistant, and elastic sealant material and includes a ring portion adapted to seal about the penis at or directly behind the glans thereof and a pair of integral strap portions projecting from the ring portion and intended to extend inwardly (proximally) along the penile shaft. The strap portions function primarily to provide catheter retention, whereas the ring portion coacts with the retained catheter and with the penis to serve primarily as a barrier against fluid backup.
The external catheter of U.S. Pat. No. 4,378,018 is provided with convolutions of graduated size in the neck region between the catheter's cylindrical body portion and its reduced drainage tube portion. Such convolutions permit axial as well as radial expansion and contraction and thereby absorb tensioning forces that might otherwise occlude the lumen or reduce effectiveness of the seal between the pad and catheter, or pad and penis, or both. In addition, the convolutions increase the internal capacity of the neck region to accommodate sudden discharges of urine, thereby reducing the possibilities of fluid backup, or disengagement of or damage to the drainage device, under such circumstances.
Conditions may nevertheless arise where a surge of fluid may create a back pressure that may weaken the adhesive seal between the pad and catheter, or between the pad and the penis, resulting in leakage. Should the neck portion of the catheter become enlarged or distorted because of fluid pressure, the forces generated by such pressure will tend to urge the inner surfaces of the catheter laterally out of sealing contact with the annular portion of the pad. Furthermore, apart from the possibility of leakage arising because of surges of fluid causing a failure of the adhesive seal, there is always the risk that gradual deterioration of that seal will occur because of exposure to the urine over an extended period, or that the material of the pad will tend to deteriorate because of continuous exposure to fluid, resulting in undesirable back flow and leakage.
U.S. Pat. No. 2,940,450 discloses a drainage device in the form of an external catheter connected to a flexible tube leading to a suitable receptacle, the catheter being held in place by drawstrings which may be tied together to produce a secure fit. In U.S. Pat. No. 3,835,857, elastic adhesive tape is wrapped about the catheter in place of drawstrings, and in U.S. Pat. No. 3,863,638 a liner is disposed between the catheter to reduce leakage and promote patient comfort. U.S. Pat. No. 4,187,851 discloses a method of forming such a liner in place by wrapping the penile shaft with a double-faced adhesive strip prior to application of the elastic external catheter.
Those devices that have the advantage of being easily and quickly applied tend to be less effective in terms of retention and prevention of fluid backup, whereas those that are more satisfactory in the latter respects are often relatively difficult to apply and more likely to cause patient discomfort and urethral constriction. Ease of application and removal are particularly important because an incontinent patient may have other disabilities that make complicated manipulations difficult if not impossible to perform. Other patents reflecting the state of the art are 364,932, 3,721,243, 3,361,857, 3,511,241, 2,891,546, 4,022,213, 3,526,227, 3,353,538, 1,423,537, 1,015,905, 3,604,424, 4,239,044, 1,490,793, 3,559,651, and 3,405,714.
One aspect of this invention lies in the recognition of the problem of maintaining effective adhesive seals under the conditions described above; a second aspect lies in recognizing that the degradation or rupture of such seals may be prevented by providing the external catheter with an elastic tapered internal sleeve disposed within the neck portion of the outer sheath. In use of the catheter, the sleeve is stretched into sealing engagement with the glans to provide a barrier that tends to prevent liquid from migrating rearwardly or proximally towards the adhesive attachment between the cylindrical portion of the catheter and the penis. Should a surge urine within the neck portion of the catheter cause back pressure, such pressure only tends to increase the effectiveness of the liquid barrier formed between the glans and the sleeve stretched thereabout. Furthermore, when an annular portion of the sleeve is in direct contact with the adhesive pad, as where the sleeve extends slightly behind (proximal to) the corona of the glans, such back pressure increases rather than diminishes the force of adhesive contact with the wearer and thereby promotes an even more effective adhesive seal.
In a preferred embodiment, the adhesive attaching means takes the form of a pressure sensitive adhesive coating along the inner surface of the sheath's cylindrical portion directly behind the sheath's tapered neck section. In some cases the adhesive coating may also be applied to a narrow annular band at the proximal extreme of the sleeve; however, in that event the band should be narrow enough that adhesive contact with the wearer is still limited to an area behind (proximal to) the corona of the glans. Instead of an adhesive coating, the adhesive means may alternatively take the form of a resilient skin-protecting adhesive pad of the type disclosed in aforementioned U.S. Pat. No. 4,378,018, particularly as shown in FIGS. 8-13 thereof. In either case, the adhesive means serves the important function of holding the sheath in position with its stretched inner sleeve retained in protective non-adhesive sealing engagement with the glans. The sleeve includes a proximal end portion, merging and permanently interated with the cylindrical body section of the sheath, and an elongated distal end portion extending and tapering distally into the sheath's neck section. The elongated distal end portion of the sleeve terminates in a reduced opening spaced axially from the distal end of the neck section and has an outer surface unsecured and normally spaced from the neck section along the full length and circumferential extent of the sleeve's distal end portion to provide an expansion space between the sleeve and the neck section. Any increase in pressure within the annular space about the sleeve only tends to urge the sleeve into tighter sealing engagement with the glans. The result is an external catheter which has the advantages of adhesive attachment in terms of patient comfort and convenience, in contrast to prior devices requiring belts, harnesses, and the like, and which at the same time provides a high degree of security against fluid backup and leakage, protects the sensitive dermal surfaces of the glans against direct exposure to urine and the excoriating effects that prolonged fluid contact might otherwise produce, and maintains an effective fluid-tight seal without the discomforts of direct adhesive contact with the glans.
The catheter may be formed in a dipping process that includes the preliminary step of stretching a pre-formed tubular member, ultimately to become the inner sleeve, over a dipping form. In its unstretched or untensioned state, the tubular member has a distal end portion that tapers and terminates in a reduced distal opening. After stretching the tubular member upon the form, the distal end portion of that member is treated to prevent liquid latex from bonding thereto. Thereafter, the form is dipped into a latex bath and the latex coating is then cured to produce the outer sheath, or at least that portion of the outer sheath surrounding the inner sleeve. When the catheter is stripped from the form, the sleeve returns to its original untensioned state, thereby creating an annular space between the outer distal portion of the sleeve and the inner surface of the sheath's neck section.
Other features, objects, and advantages of the invention will become apparent from the drawings and specification.